The nanoporous thermal insulating material was prepared by using fumed silica, SiC powder and glass fiber as starting materials, the appropriate thickness of the nanoporous thermal insulating material lined in ladle was discussed by the simulation method, and the effect of its application as ladle lining was investigated. The results show that the thermal conductivity of the nanoporous thermal insulating material prepared in composition of fumed silica∶SiC powder∶glass fiber=75∶20∶5 (in mass) is 0.023 W·m^-1·K^-1  at 1 000 ℃, the appropriate thickness of the nanoporous thermal insulating material lined in ladle is ≤ 5 mm and the average temperature of the ladle outside surface when lined with the nanoporous thermal insulating material is 95 ℃ lower than that with the ordinary thermal insulating material.